Error using readtable (line 318) Matlab R2021a

I try to open my file and it answers me that

K>> t=readtable(sprintf('F:\\sub_%i.xlsx',n))

Error using readtable (line 318)

Search term must be a text or pattern scalar.

And when i only use the readtable function it says me that

K>> readtable

Error using readtable (line 318)

Not enough input arguments.

And when i open the readtable script, it opens that and the variable "ME" at the end seems to be the problem since it is not defined anywhere

function t = readtable(filename,varargin)
[varargin{1:2:end}] = convertStringsToChars(varargin{1:2:end});
names = varargin(1:2:end);
try
    if any(strcmpi(names,"Format"))
        t = matlab.io.internal.legacyReadtable(filename,varargin);
    else
        func = matlab.io.internal.functions.FunctionStore.getFunctionByName('readtable');
        C = onCleanup(@()func.WorkSheet.clear());
        t = func.validateAndExecute(filename,varargin{:});
    end
catch ME
    throw(ME)
end

If someone could help me it eould be really great,

thanks!

[Rik]

n=1;
sprintf('F:\\sub_%i.xlsx',n)

ans = 'F:\sub_1.xlsx'

The file name seems to evaluate to a valid file name, so that part isn't the problem.

Your assertion that ME is undefined is incorrect: this is the way exceptions are caught in Matlab. The catch keyword will create the ME variable if and when an error occurs.

I expect this to be an issue with the file. Can you attach it to your question (and mention the value of n)?

[Zoé]

This is the beginning of the boucle of my script and i put the first file on attachments (n depends on the the number of the files since i have 8 different files with sub_x)

%%
N=1;
Nvol = 202
%%
for n=1:N
    s = sprintf('sub_%i',n);
    
    t=readtable(sprintf('F:\\sub_%i.xlsx',n),'NumHeaderLines',0, 'ReadVariableNames',true);

[Cris LaPierre]

Your code runs without errors here. I also checked in R2021a and again, it ran without error.

Can you provide more details about your system and setup? Perhaps try restarting MATLAB and seeing if just running the code below works for you as well?

n=1;
t=readtable(sprintf('sub_%i.xlsx',n))

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

t = 240×6 table
    Condition    Target_RT    Target_OnsetTime    Target_RTTime     Run     RTTime_Onset
    _________    _________    ________________    _____________    _____    ____________

      {'2'}          653              43614             44267      {'1'}        0.653   
      {'3'}          549              47613             48162      {'1'}        4.548   
      {'1'}          803              50613             51416      {'1'}        7.802   
      {'3'}          321              53579             53900      {'1'}       10.286   
      {'2'}          426              65577             66003      {'1'}       22.389   
      {'2'}          375              70577             70952      {'1'}       27.338   
      {'2'}          484              73576             74060      {'1'}       30.446   
      {'1'}          604              76576             77180      {'1'}       33.566   
      {'2'}          370              80576             80946      {'1'}       37.332   
      {'1'}          658              85575             86233      {'1'}       42.619   
      {'2'}          358              88574             88932      {'1'}       45.318   
      {'1'}          582              96573             97155      {'1'}       53.541   
      {'2'}          449         1.0559e+05        1.0604e+05      {'1'}       62.424   
      {'2'}          374         1.1259e+05        1.1296e+05      {'1'}       69.348   
      {'3'}          392         1.1859e+05        1.1898e+05      {'1'}       75.365   
      {'1'}        240.9         1.2259e+05        1.2283e+05      {'1'}       79.214   

function t = readtable(filename,varargin)
[varargin{1:2:end}] = convertStringsToChars(varargin{1:2:end});
names = varargin(1:2:end);
try
    if any(strcmpi(names,"Format"))
        t = matlab.io.internal.legacyReadtable(filename,varargin);
    else
        func = matlab.io.internal.functions.FunctionStore.getFunctionByName('readtable');
        C = onCleanup(@()func.WorkSheet.clear());
        t = func.validateAndExecute(filename,varargin{:});
    end
catch ME
    throw(ME)
end
end

[Rik]

N=1;
for n=1:N
    s = sprintf('sub_%i',n);
    t=readtable(sprintf('sub_%i.xlsx',n),'NumHeaderLines',0, 'ReadVariableNames',true);
end

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

As you can see, this code runs without error on R2023a.

What does the line below return on your machine?

clc,strrep(which('readtable','-all'),matlabroot,'')

ans = 2×1 cell array
    {'/toolbox/matlab/iofun/readtable.m'                                    }
    {'/toolbox/shared/io/general/+matlab/+io/@ImportOptions/ImportOptions.m'}

Answer 1

[dpb]

t=readtable('sub_1.xlsx');

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

head(t)

    Condition    Target_RT    Target_OnsetTime    Target_RTTime     Run     RTTime_Onset
    _________    _________    ________________    _____________    _____    ____________

      {'2'}         653            43614              44267        {'1'}        0.653   
      {'3'}         549            47613              48162        {'1'}        4.548   
      {'1'}         803            50613              51416        {'1'}        7.802   
      {'3'}         321            53579              53900        {'1'}       10.286   
      {'2'}         426            65577              66003        {'1'}       22.389   
      {'2'}         375            70577              70952        {'1'}       27.338   
      {'2'}         484            73576              74060        {'1'}       30.446   
      {'1'}         604            76576              77180        {'1'}       33.566   

t=readtable('sub_1.xlsx','numheaderlines',0,'readvariablenames',1);

Warning: Column headers from the file were modified to make them valid MATLAB identifiers before creating variable names for the table. The original column headers are saved in the VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.

head(t)

    Condition    Target_RT    Target_OnsetTime    Target_RTTime     Run     RTTime_Onset
    _________    _________    ________________    _____________    _____    ____________

      {'2'}         653            43614              44267        {'1'}        0.653   
      {'3'}         549            47613              48162        {'1'}        4.548   
      {'1'}         803            50613              51416        {'1'}        7.802   
      {'3'}         321            53579              53900        {'1'}       10.286   
      {'2'}         426            65577              66003        {'1'}       22.389   
      {'2'}         375            70577              70952        {'1'}       27.338   
      {'2'}         484            73576              74060        {'1'}       30.446   
      {'1'}         604            76576              77180        {'1'}       33.566   

Seems just fine although as shown you don't need either input parameter for the "plain vanilla" file...I wondered if the two of telling it no header lines and to read variable names were, perhaps, fighting each other, but it appears it figured it out.

As for the filename generation, I'd suggest using something more like

dataDir='YourDataFolder';
d=dir(fullfile(dataDir,'sub*.xlsx'));           % return the dir() struct matching files
for i=1:numel(d)                                % iterate over collection
  t=readtable(fullfile(d(i).folder,d(i).name);  % read each in turn
  ... do whatever with each here...
end

Whatever was the cause of the error in the original, it wasn't in what we've been able to see that you've posted.

Would need the actual script and data file that created the error to diagnose; what we can see is ok...